Immediate objectives of the proposed research are: (1)\Solubilization, separation, and purification of the N-acetylglucosaminyltransferases catalyzing the biosynthesis in vitro of branched Ii-core structure using specific affinity columns from mouse lymphoma. Presence of either of these enzymes in other mouse B-\and T-lymphomas and their possible roles in regulation of Ii-antigen expression on the tumors will be studied. (2)\Using affinity chromatography, betaGalT-4, which catalyzes the biosynthesis in vitro of core nLcOse4Cer, will be separated from betaGlcNAcT and attempts will be made to further purify this betaGalT-4. Exact chemical linkage of the product of betaGalT-4-catalyzed reaction will be determined by permethylation of the product Gal-[14C-Ac]LcOse3Cer. (3)\Different kinetic parameters of these enzymes (betaGlcNAcTs and betaGalT-4) will be studied after further purification of the solubilized enzymes. The major emphasis of this proposal would be to determine the possible relationship between tumorigenicity and expression of Ii-antigen in these mouse B-\and T-lymphomas. (A)